Functional magnetic resonance imaging (fMRI)

What is fMRI?

Functional Magnetic Resonance Imaging (fMRI) is a technique that measures brain activity when people are performing some kind of task. The scanner is a large, open ended, cylindrical tube that contains a very powerful magnet. When a part of the brain is being used it consumes more oxygen which results in extra oxygen being supplied to that part of the brain. It is these changes in blood oxygenation level that fMRI measures. This approach allows us to see very precisely (within about 3-5mm) what parts of the brain are being used when performing a particular task which provides great insight into mental processes.

What is MRI?

MRI works in a very similar way to fMRI and provides extremely detailed pictures of internal regions of the body (such as the brain). During MRI you typically do not have to perform any task, but can just relax while the scan (which usually takes between 5-10 minutes) is taking place.


(© Peninsula MR Research Centre, Exeter; for more MRI images, check the website of the PMRRC)

Is it safe?

fMRI is a completely safe technique, and there are no side-effects. You are not injected with any nasty substances and all you have to do is lie inside a scanner and perform a simple task. The machine may appear imposing to some, as does the idea of having your brain scanned, but the environment is perfectly safe and for most people it is surprisingly relaxing.

The only restriction on volunteers is that, because of the powerful magnet, it is important that you do not have any metal implants or have not undergone surgery in the last 6 months. Normal or gold fillings in your teeth are fine. If you have any body piercings, they will have to be removed on the day. If you wear glasses then you will have to wear contact lenses while you are in the scanner if you have them.

Where is the scanner

Exeter's scanner is on St. Luke’s campus in the Peninsula College of Medicine and Dentistry. There is a map on the university website which shows where to go: centres.exeter.ac.uk/pmrrc/direction.

Would you like to know more? www.fmrib.ox.ac.uk/education/fmri/introduction-to-fmri.